‘Yes, sir. But if you don’t object I’m going to follow it up a little longer. I think we are uncovering something really big.’

After Spoder hung up I stared at the dark computer monitor, then rebooted.

I worked hard on my novel for another five days, and by intensive redrafting I soon reached the same part of the story I had been writing before I went to Dearth. I had completed a roughly equal number of revised pages, but the content of the book was now so different that there was hardly any equivalence. Mutability of literature turned out to be an effective spur to rewriting. I was satisfied the four main characters were fleshed out. They all knew of each other but their lives remained separate. There was a looming sense of danger, but it was not focused individually on any one of the four.

Although I had already mentally picked out who my murderer was eventually to be, exposed climactically in the final pages of the novel, their tracks were carefully blurred with those of the other three.

One of those might or might not turn out to be the victim – I had yet to decide.

Unexpectedly, I felt myself easing off the novel again. Once I was through the intensive period of recovery and rewriting, my afternoons relaxing on the patio deck outside my study gradually grew longer. I watched more TV in the evenings. I still kept up a daily output of new pages but I knew I was cruising, not driving hard.

One afternoon, as I passed through the bedroom in search of a book, I noticed the key card I had inadvertently kept when I left the hotel in Dearth City. It was on the bedside table, partly covered by the base of my reading lamp. That’s where I had put it earlier when emptying my pockets. I knew the hotel wanted it back. I kept meaning to look up the address and return it. I had seen the card every day, but had never got around to doing the necessary search. It felt low on my priorities.

I picked up the card, intending to do something with it at last, but as I held it and turned it over in my fingers I saw something I had not noticed before.

The top of the card, the laminated side, was familiar: it had a computer chip embedded in the centre, slightly towards one end. This presumably was what was read by the key mechanism in the hotel door. An arrow lightly engraved in the shiny white surface indicated the direction in which the card should be pressed into the slot.

But there was a second chip, or several more, buried on the underside of the card. These were less prominent, nano chips, visible as a tiny thin strip of serrated metal bonded into the plastic. The strip was less than a centimetre long.